A Tracing Pollution Footprints: A Spatio-Temporal Remote Sensing Study of Urban Growth and Road Expansion in Bhiwadi (2016–2025)

Abstract

Rapid industrialization and urban expansion have significantly altered the environmental landscape of Bhiwadi, a prominent industrial hub in Rajasthan and part of India’s National Capital Region (NCR). This study employs multi-temporal Sentinel-2 imagery and geospatial techniques to analyze urban growth, land use/land cover (LULC) transitions, and road network densification from 2016 to 2025, with a focus on their implications for pollution vulnerability. The Normalized Difference Built-up Index (NDBI) and Normalized Difference Vegetation Index (NDVI) were used to quantify urban expansion and vegetation dynamics, while road networks were extracted through false color composites and analyzed for density variations. Results reveal a 30.8% increase in built-up area, accompanied by an 18.1% decline in vegetation and a 161% rise in bare land, highlighting a substantial loss of natural pollutant sinks. The road network expanded by 50.5%, with the construction of a railway line in 2018 catalysing further connectivity and industrial sprawl, particularly in the north-central corridor. These transformations indicate an infrastructure-led urbanization process closely tied to deteriorating air quality, as vegetation loss, dust resuspension from bare land, and vehicular emissions collectively intensify pollution levels. The integrated spatial analysis identifies critical “triple-impact” zones where built-up growth, vegetation decline, and high road density converge, underscoring their heightened pollution vulnerability. The results stress the importance of proactive urban planning interventions through vegetative buffers, dust suppression measures, and cleaner transportation options, to address the ecological impacts of accelerated industrial development in Bhiwadi.